The invention relates to a device for stroboscopically testing the ignition timing of an internal-combustion motor.
Such devices are well known in the art and generally comprise a flash lamp of the ionised-gas type having a triggering electrode to which the triggering voltage of a suitable trigger circuit is applied, which trigger circuit is adapted to be controlled by impulses received from the ignition system of the motor to be tested. The flashes of the flashlamp are used to stroboscopically illuminate a rotating part of the motor to be tested, generally a test mark provided for that purpose on the flywheel of the motor.
In the conventional devices of this kind the impulses controlling the trigger circuit are supplied to this circuit through a test lead having a connector for the galvanic or inductive connection to the spark plug or spark plug cable of the first cylinder of the motor (see for instance the U.S. Pat. No. 3,497,798) or to the primary winding of the ignition coil of the ignition system of the motor (see the British Pat. No. 684,791), which is however unpractical. The known devices are usually provided with a conventional xenon-filled flash lamp having lead wires projecting from the envelope of the lamp which must be connected by soldering so that this flash lamp cannot be exchanged by the user himself. Finally, the devices of the prior art have generally such thickness dimensions that, in many conventional motors, they cannot be properly inserted into the restricted space between the flywheel and the ventilator of the motor for properly illuminating the test mark on the flywheel for stroboscopic observations.